Adding docs to the `$_fields` property of the auth `Form` adapter.
Adding docs to the `$_fields` property of the auth `Form` adapter.

m4rcsch/lithium-core-library,whowgames/lithium,whowgames/lithium,qoqa/lithium,davidpersson/lithium,pixelcog/lithium,datachand/lithium,SensCritique/lithium,wbeater/lithium,UnionOfRAD/lithium,graphis/lithium,datachand/lithium,jails/lithium,m4rcsch/lithium-core-library,davidpersson/lithium,SensCritique/lithium,graphis/lithium,mehlah/lithium,wbeater/lithium,muyehub/lithium,qoqa/lithium,muyehub/lithium,UnionOfRAD/lithium,jails/lithium,pixelcog/lithium,mehlah/lithium